This is indeed probably due to new HW.
The old models with FW1.x are not compatible with FW2.x and vice-versa..
Interestingly they replaced the "ecomb" with the new "Aladdin " binary.
The Aladdin bin is 22622469 bytes in size, while the ecomb has just 5113340 bytes (latest FW). The Aladdin FW is 4x bigger! Can it be the same bin as used by the Plus model?
This single FW works for 15, 32 and 75 models. But hold your horses: the FW has an individual folder with the bin file for the FPGA. I don't know if the HW is really the same for 32 and 75 models, but chances are, it might actually be. --> any volunteer with a new FW 2.x model wanting to test if you can upgrade the 15 to 32 or 75, or the 32 to 75? This is interesting!
Finally, despite the new public hack, it is good news that the hash used remains the same.
Other interesting things: this firmware activates a FTP daemon and a VNC daemon. These did not exist in FW1.x. My guess is that the base HW has a faster CPU? Nah, I really think they use the same base HW for SSA-X/SSA-P/SSA-R/SVA (note that the SVA-R has an extra RT board fitted). Probably the board/device is not fully populated for higher models. This makes sense to keep prices competive. The SSA line has probably been effectively stopped from a HW point of view and for commercial reasons there is a new low-cost SSA-X based on the same HW platform as the SSA-P/SVA
UPDATE: I just checked and the Aladdin bin of the lates FW for the SSA-P is 13,856,588 bytes in size, half the size of the new SSA-X bin. That is strange!
UPDATE2: Apart from a different CRC on the Aladdin bin, all remaning files have the same CRC (SSA-X vs SSA-P) - All? Well, I checked most and they match. Conclusion: BOTH DEVICES USE THE SAME HW PLATFORM!
Regards,
Vitor